Water → 5,7-dichloro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Beteiligte Stoffe

Reaktionsschritte

To a suspension of 4,6-dichloroindolin-2,3-dione (5.95 g) in acetic acid (95 ml) was added chromium trioxide (16 g) over a period of 15 minutes at 60° C. with stirring and the mixture was stirred at 70°-75° C. for 1 hour. After cooling, the reaction mixture was poured into water (360 ml) and the resulting precipitates were collected by filtration. The filtrate was extracted with ethyl acetate. The extract was washed with water and dried. Removal of the solvent gave a residue, which was combined with the precipitates. Recrystallization from isopropyl ether gave 5,7-dichloro-2H-3,1-benzoxazine-2,4(1H)-dione (2.85 g).

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